Drive Shaft FAQ….

Drive Shaft FAQ:

  1. What is a conversion u-Joint?
  2. Is it possible to have 2 different u-joint sizes on my drive shaft
  3. What causes drive shaft vibration?
  4. Why does a drive shaft twist or bend?
  5. What causes universal joints to break?


1.  What is a conversion Joint?

A conversion u-joint is a universal joint with two different size caps, which is used when you want to use a larger series driveshaft than what your vehicle’s transmission or rear differential already has.  For example: If you have 1330 series end yoke on the transmission or rear differential but you want to use a stronger 1350 series drive shaft.  A conversion joint would then be used because it will have two caps that are 1330 series and the other two caps would be 1350 series sized caps.

2. Is it possible to have 2 different U-joint sizes on my drive shaft?

Yes. This is a common, especially if  the transmission or rear end of your vehicle has been modified.  If you think that you have two different sizes on the same u-joint, you may have a conversion joint.

3.   What causes drive shaft vibration?

There can be many reasons for a drive shaft to vibrate.  One reason for drive shafts to vibrate is components beginning to wear out.  The most common component related reasons for a drive shaft to vibrate:

  1. Worn or Broken u-joint—MSI U-joint Failure Guide
  2. Worn out spline on slip yoke or tube shaft
  3. Drive shaft tubing damage—MSI Tubing Failure Guide
  4. Balance weight missing
  5. Lack of grease—MSI Driveline Lubrication Guide

***ALWAYS have your drive shaft balanced after replacing components ***

Aside from have components damaged or worn out that cause your driveshaft to vibrate.   There are many other technical reasons for drive shaft to vibrate:

  1. Drive shaft is the improper length
  2. Improper drive shaft angle
  3. Drive shaft out of phase
  4. Wrong size u-joints for application

4.   What causes a drive shaft to twist or bend?

Please refer to our Tubing Failure Page

5.   What causes universal joints to break?

Please refer to our Universal Joint Failure Page